Method of Recovering Indium Oxides From Low Grade Indium Containing Residue

Abstract

A method for recovering indium oxide from a indium-containing residue includes putting tin and an indium-containing residue into a melting furnace, melting the indium-containing residue, generating fume oxide through a reaction of indium and oxygen in the melting furnace, flowing the exhaust gas into a scrubber, spraying a scrubber-circulating liquid toward the exhaust gas in the scrubber, collecting indium oxide included in the exhaust gas with the scrubber-circulating liquid through a gas-liquid contact, performing a first collection of indium oxide through a separation of solid from liquid in a centrifuge, flowing the exhaust gas passed through the scrubber into a bag filter, performing a second collection of indium oxide included in the exhaust gas in the bag filter, flowing the exhaust gas passed through the bag filter into an absorption tower, and removing odors and toxic components generated in the exhaust gas in the absorption tower filled with an activated carbon.

What is claimed: 
     
         1 . A method for recovering indium oxide from an indium-containing residue, the method comprising:
 (a) preparing an indium-containing residue generated in a wet leaching or solvent extraction process to extract indium (In) contained in indium-tin oxide;   (b) putting tin into a melting furnace;   (c) putting the indium-containing residue into the melting furnace, melting the indium-containing residue, and generating fume oxide through a reaction of indium and oxygen in the melting furnace;   (d) flowing an exhaust gas including the fume oxide into one or more scrubbers, and spraying a scrubber-circulating liquid toward the exhaust gas in the one or more scrubbers;   (e) collecting indium oxide included in the exhaust gas with the scrubber-circulating liquid through a gas-liquid contact to send to a centrifuge, and performing a first collection of indium oxide through a separation of solid from liquid in the centrifuge;   (f) flowing the exhaust gas passed through the scrubbers into a bag filter, and performing a second collection of indium oxide included in the exhaust gas in the bag filter; and   (g) flowing the exhaust gas passed through the bag filter into an absorption tower, and removing odors and toxic components in the exhaust gas in the absorption tower filled with an activated carbon.   
     
     
         2 . The method of  claim 1 , further comprising:
 recovering indium oxide from skimming dross formed on a surface of a melt remaining in the melting furnace after the step (c); and   obtaining coagulated crude Sn by casting the melt remaining in the melting furnace into a mold.   
     
     
         3 . The method of  claim 1 , wherein a carbon is additionally put into the melting furnace to accelerate melt-oxidation in the step (c). 
     
     
         4 . The method of  claim 3 , wherein the carbon is added at a rate of 1/10 to 1/5 (weight ratio) with respect to a total content of indium contained in the indium-containing residue. 
     
     
         5 . The method of  claim 1 , wherein sodium hydroxide (NaOH) is added in the scrubber-circulating liquid to remove chlorine (Cl) components contained in the exhaust gas. 
     
     
         6 . The method of  claim 1 , wherein the melting furnace is heated to a temperature higher than 600° C. to increase melt-oxidation effectiveness. 
     
     
         7 . The method of  claim 1 , wherein the scrubber-circulating liquid, which is discharged from the centrifuge is reflowed into the one or more scrubbers and circulated. 
     
     
         8 . A method for extracting indium oxide, the method comprising:
 (a) putting tin into a melting furnace;   (b) putting an indium-containing residue into the melting furnace, melting the tin and the indium-containing residue, and generating an exhaust gas that includes indium oxide from a reaction of indium and oxygen in the melting furnace;   (c) flowing the exhaust gas into a scrubber and contacting a scrubber-circulating liquid with the exhaust gas to transfer indium oxide from the exhaust stream to the scrubber-circulating liquid;   (d) collecting the scrubber-circulating liquid and sending the scrubber-circulating liquid to a centrifuge, and performing a first collection of indium oxide through a separation of indium oxide from the scrubber-circulating liquid in the centrifuge;   (e) flowing the exhaust gas from the scrubber to a bag filter, and performing a second collection of indium oxide included in the exhaust gas in the bag filter; and   (f) flowing the exhaust gas from the bag filter into an absorption tower, and removing odors and toxic components in the exhaust gas in the absorption tower filled with an activated carbon.   
     
     
         9 . The method of  claim 8 , further comprising:
 recovering indium oxide from skimming dross formed on a surface of a melt remaining in the melting furnace after the step (b); and   obtaining coagulated crude Sn by casting the melt remaining in the melting furnace into a mold.   
     
     
         10 . The method of  claim 8 , wherein a carbon is additionally put into the melting furnace to accelerate melt-oxidation in the step (b). 
     
     
         11 . The method of  claim 10 , wherein the carbon is added at a rate of 1/10 to 1/5 (weight ratio) with respect to a total content of indium contained in the indium-containing residue. 
     
     
         12 . The method of  claim 8 , wherein sodium hydroxide (NaOH) is added in the scrubber-circulating liquid to remove chlorine (Cl) components contained in the exhaust gas. 
     
     
         13 . The method of  claim 8 , wherein the melting furnace is heated to a temperature higher than 600° C. to increase melt-oxidation effectiveness. 
     
     
         14 . The method of  claim 7 , wherein the scrubber-circulating liquid, which is discharged from the centrifuge, is reflowed into the scrubber and circulated.